1. Field of the Invention
The present invention relates to a clathrate compound of hinokitiol or a metal salt of hinokitiol and to a composition containing the clathrate compound.
2. Prior Art
Hinokitiols have a high antibacterial activity against various Gram-positive bacteria and Gram-negative bacteria and have been known to exhibit an antibacterial activity against mesitylene-resistant staphylococcus aureus (MRSA) in recent years. By using the characteristics of a hinokitiol based on its antibacterial activity, it is utilized in various applications such as medicament, fragrant cosmetic and food fields.
However, hinokitiols have the drawbacks of high sublimation, deficient thermal stability and strong corrosiveness to metals, e.g.,stainless, as well as poor solubility in water.
For this, trials for water-solubilization of hinokitiols have been made and clathrate compounds of disbranched cyclodextrins (hereinafter described as xe2x80x9cdisbranched CDxe2x80x9d as the case may be) have been proposed (Japanese Patent Application Publication (JP-B) No. 1-53,856). However, the solubilities of clathrates of disbranched CD in water at 15xc2x0 C. are 13 g/100 ml in the case of xcex1-CD clathrates containing 38 mol% of a hinokitiol, 0.3 g/100 ml in the case of xcex2-CD clathrates containing 92 mol% of a hinokitiol and 0.9 g/100 ml in the case of xcex3-CD clathrates containing 60 mol% of a hinokitiol. The solubility of each clathrate including the xcex2-CD clathrate is insufficient. Moreover, hinokitiols have a solubility insufficient to be formulated into fragrant cosmetics, health and sanitary materials or medicaments.
Present inventors have conducted various studies to solve the above problems and as a result found that the solubilities of hinokitiols in water, fragrant cosmetics, health and sanitary materials and medicaments can be improved in contrast with clathrates of disbranched CD without damaging the antibacterial activity of a hinokitiol by clathration of hinokitiols by using branched cyclodextrin (hereinafter described as xe2x80x9cbranched CDxe2x80x9d as the case may be). The present inventors have also found that the sublimation, the corrosive characteristics and the like of a hinokitiol can be improved and the invention was thus completed.
According to a first aspect of the present invention, there is provided a clathrate compound comprising clathration of hinokitiols by using a branched cyclodextrin.
In preferred embodiments, the hinokitiols are at least one compound selected from the group consisting of a hinokitiol and a metal salt of hinokitiol;
the branched cyclodextrin is a branched xcex2-cyclodextrin; and
the clathrate compound is a water-soluble powder.
According to another aspect of the present invention, there is provided a composition comprising the clathrate compound.
In preferred embodiments, the composition comprising the clathrate compound has an antibacterial activity; and
the composition comprising the clathrate compound is a composition selected from the group consisting of a cosmetic composition, a bath agent, a detergent and an oral composition.